Pros&Cons of PEX-A, PEX-B, PEX-C Tubing

posted by:iwissecho

2018-09-03

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The cross-linked polyethylene tubing(PEX) that provides an excellent option for plumbing, radiant and hydronic systems in both residential and commercial plumbing applications is widely used in America, Europe as well as Australia. Each area has its standard in PEX installation which is searchable on www.astm.org. Hope you can help yourself choosing the best PEX type for your upcoming domestic or industrial projects after reading this essay.

Manufacture Process of PEX Tubing

The PEX-A & PEX-B & PEX-C are all processed by Crosslinking, which is a chemical reaction that occurs between polyethylene polymer chains.

Crosslinking causes the HDPE to become stronger and resistant to cold temperature cracking or brittleness on impact while retaining its flexibility.

The three methods of crosslinking HDPE are:

PEX-A : Peroxide (Engels) method. During the manufacturing process, free radicals are created when HDPE polymer is melted and cross-links between molecules occur at temperatures that exceed the decomposition temperature of the polymer

PEX-B : Silane (Moisture Cure) Method. After the extrusion process, cross-linking where links between the molecules of the HDPE using a catalyst and exposing PEX tubing to hot water. This type of PEX is the most

PEX-C : Radiation (Electronic Irradiation) method. Cross-linking of the molecules is done after the process of extrusion by exposing the pipe to an electron radiation beam. The radiation emitted allows to break the existing links between molecules of the polymer and initiate cross-linking process.

Pros&Cons of PEX-A, PEX-B, PEX-C Tubing

PEX-A

The most flexible and highest quality tubing on the market, which makes it the most expensive of all those 3 types.

The kinks in the pipe could be repaired by merely heating the pipe with a heat gun for it is more elastic than PEX-B.

The wall thickness of PEX-A systems is normally greater than PEX B because it has a lower burst strength and hence requires the greater thickness to cope with the same operating pressures.

As a result of the thicker wall of PEX-A pipe, it will generally have a lower SDR and hence a lower flow rate.

The pipe is expanded around the fitting rather than the fitting being fit inside the pipe. This may make fittings harder to install if you’re working in cold conditions.

Tips: This PEX is slightly more flexible than the other types at temperature above 60oF. However, below this temperature, PEX-B tends to be more flexible and offer an advantage during installation in colder climates.

Several industry participants claim that the PEX-a method yield more flexible tubing than the other methods

PEX-B

The cheapest one of those 3 types.

The expansion fitting s couldn’t work with PEX-B.

The flow rate is superior in comparison to PEX-A, as it is often rated for higher pressure than PEX-A.

The most commonly use PEX in North America, including compression, pushfit and copper crimp rings. It is more affordable because is is more rigid.